Mrs May reportedly did not speak to senior members of Cabinet before reports emerged of her plan to avoid the return of a hard border to carry out customs checks between the two countries.

According to the Guardian, Brexit Secretary David Davis only became aware of the term "alignment" being used late on Sunday night.

A Whitehall source insisted that simply reflected “how late the text was being worked on”.

The proposal quickly fell apart, and Mr Davis came out yesterday and vowed not to leave Northern Ireland in the single market or customs union after Brexit.

The Brexit Secretary said it was “emphatically” not the case that the Government was mulling leaving Northern Ireland part of EU institutions while the rest of the UK leaves.

One Cabinet source told the Daily Telegraph: “It seems that either Northern Ireland is splitting from the rest of the UK or we are headed for high alignment with the EU, which certainly hasn’t been agreed by Cabinet. The Prime Minister is playing a risky game.”

Sources also told the paper that Mrs May had failed to get support from her ministerial team on the "regulatory alignment" proposition and it had only been raised briefly during Tuesday's Cabinet meeting.

"There is a genuine fear that we are heading for a soft Brexit… It seems that the plan was to square it with the EU and come back and bounce the DUP and the Cabinet into accepting her position," a source said.

It comes after DUP leader Arlene Foster - whose 10 MPs prop up Theresa May's minority government - pulled the plug on an exit arrangement between the UK and Brussels at the eleventh hour on Monday.

She dramatically intervened when leaked reports revealed the Prime Minister was on the verge of a deal that would see just Northern Ireland retain "regulatory alignment" with the bloc to preserve its open border with the Republic.

The news sparked fears among DUP figures and other devolved authority leaders that Northern Ireland could be effectively left in the European single market and customs union while the rest of the UK left.

But hauled before the Commons yesterday, Mr Davis said: “The suggestion we might depart the EU but leave one part of the UK behind still inside the single market and customs union is emphatically not something the UK government is considering."

graham669

11:01 on 6th December 2017

The main reason that Mayhem and this government are driving hell bent for brexit at any cost, in 2019, is pure greed. Obviously this also applies to gove and johnson.
They and their billionaire supporters don't want to have to pay full tax, the new EU Anti Tax Avoidance legislation, comes into effect in January 2019. The only way to avoid it becoming UK law is brexit.
Read this carefully: https://ec.europa.eu/taxation_customs/business/company-tax/anti-tax-avoidance-package/anti-tax-avoidance-directive_en